Pillow block



INVENTOR. CARL HlLTON C. HILTON PILLOW BLOCK Original Filed April 16,1962 Oct. 3, 1967 United States PatentO 3,345,116 PILLOW BLOCK CarlHilton, Chicago, Ill., assignor to Masten Corporation, Chicago, 111., acorporation of Illinois Original application Apr. 16, 1962, Ser. No.187,872, now Patent No. 3,192,607, dated July 6, 1965. Divided and thisapplication June 1, 1965, Ser. No. 460,196

1 Claim. (Cl. 308-72) ABSTRACT OF THE DISCLOSURE A pillow blockcomprising a one-piece rigid housing formed with a spherical bore, and abearing composed of elastic sintered powdered metal material formed witha cylindrical axial bore and a substantially spherical outer surfacesnugly pivotally disposed in and embraced by the defines of saidsubstantially spherical bore, the outer surface of said bearing onlybeing slightly out-of-round and retained in said housing againstrotation on its axis.

This application is a division of Ser. No. 187,872, filed Apr. 16, 1962,now Patent No. 3,192,607 issued July 6, 1965.

This invention relates to the production of a novel pillow block. 1

More particularly the present invention relates to a new and improvedself-aligning pillow block and to the method of making same. 1 i

It is a particular object of the present invention to provide a novelone-piece pillow block wherein the bearing is non-rotatably but.pivotally retained therein whereby self-aligning bearings are providedfor journaling the ends of a rotatable shaft.

It is a further object of the present invention to provide a method andmeans for casting a one-piece metal housing about a pre-formed bearingcomposed of elastic material and whereby after casting the bearingreadily separates from the housing to the extent that it can be pivotedwithin but not disengaged from the housing.

In general, the unit of the present invention comprises an inner bearingmember of elastic material such as sintered powdered metal having aspherical outer diameter and a cylindrical inner diameter or bore. Thespherical outside diameter of the bearing is substantially enclosed by arigid one-piece metal housing cast thereabout. The spherical outerdiameter of the bearing permits it to pivot within the rigid housing toallow for alignment of a shaft journaled in the bearing.

Large scale commercial production of a unit of the foregoing type hasbeen restricted at the present time, the basic problem therein beingcasting of a movable spherical insert into a rigid housing and tocompensate for the contraction of the housing on cooling. Without somemeans of compensating for this contraction, the insert is locked inplace and as a result cannot be pivoted. One method for compensating forthis contraction is to coat the insert with some material, such as alubricant, which will be dissipated either in the casting process orafterward. The prime reason for making the latter impractical forconsistent large scale commercial production is that of maintaining auniform coating on the insert and controlling the dissipation of thecoating. Another disadvantage of the aforesaid method is that whensufiicient coating is obtained for subsequent pivoting of the insert,some means must be introduced to keep the insert from spinning on itsaxis.

The difliculties of the prior practices are overcome by the presentinvention which employs a pre-formed bearing composed of elasticmaterial such as the aforesaid porous sintered powdered metalcomposition. Such porous sintered powdered metal material is elasticwithin limits and has properties of expansion and contraction and a highdegree of elasticity, and these properties are taken advantage of in thepresent invention.

Other objects and advantages of the present invention together with itsdetails of construction, arrangement of parts and economies thereof willbe apparent from a consideration of the following specification andaccompanying drawings, wherein:

FIG. 1 is a perspective view of a unitary pillow block formed inaccordance with the present invention, and wherein a bearing of thecharacter aforesaid is pivotally disposed and retained within aone-piece metal housing cast thereabout, the housing being of thetwo-bolt flange mounting type.

FIG..2 is a section through a one-piece metal housing cast around and infirm embracing engagement with a sintered powdered metal bearing.

FIG. 3 is a sectional view of a die component for compressing theunitary assembly of FIG. 2.

FIG. 4 is a section through the die of FIG. 3 showing the unit of FIG. 2compressed therein by means of a ram.

FIG. 5 is a section on the line 55 of FIG. 4.

FIG. 6 is a view showing the movement of a shoulde-red ram into thecavity of the die and contained pillow block assembly of FIG. 4.

FIG. 7 is a section on the line 7-7 of FIG. 6.

FIG. 8 is a section similar to that of FIG. 7 but with the pillow blockremoved from the ram and die components of FIG. 6. i

Referring to the'drawings, the reference numeral 10 generally indicatesa one-piece metal housing, for'example, aluminum, cast about the bearinggenerally indicated at 11. The housing is formed with a pair of flanges12, 12 each having a hole 13 for reception of a mounting bolt. It will,of course, be understood that the illustrated pillow block unit is forthe purpose of illustration and not limitation. Thus, for example, thehousing may have a threebolt flange mounting, and in lieu of the axis ofthe bearing 11 being parallel to the axes of the bolt holes 13, 13, itwill be understood that the unit may be in the form of the standardmounting wherein the aXes of the bolt holes 13, 13 are perpendicular tothe axis of the bearing 11. Of course, the flanges 12, 12 will then beat an angle of 90 to that shown in the illustration of FIG. 1.Alternatively the housing may be formed without attachment flanges sothat the outer surface of the portion which embraces bearing 11 iscylindrical and is later pressed into a cylindrical holder by the user.

The bearing 11- as employed in the present invention, is pre-formed ofconventional powdered metals, typical compositions of which are 90%copper and 10% tin; 77.5% copper, 7.5% tin and 15% lead; 25% copper andiron; 20% copper, 79.5% iron, and 0.5% carbon, and the like. A furtheralternative can be straight iron. These compositions are given for thepurpose of illustration and not limitation; The bearings are composed ofcompressed powders which are sintered in conventional manner to resultin compositions having a resilient spongelike character. These areconventionally employed for selflubricating bearings in that they areporous and can contain approximately 25% of lubricating oil by volumestored in the tiny interconnected pores of the pre-formed bearing, thistype being known as an Oilite bearing.

As shown in FIG. 2, the bearing 11 is formed initially with acylindrical bore 14 and a spherical outer surface 15. In casting thehousing 10 about the bearing 11 in a suitable mold or die, not shown,the bearing 11 is first seated on a core pin and a one-piece housing 10cast thereabout.

As a result, the housing 10 is formed with a mating spherical surfacebore 16. Desirably also and for facility in subsequent pivoting as willbe explained, the altitude of the spherical seat 16 of the housing 10 isless than that of the spherical segment surface 15 of the bearing 11.

The housing material metal as it cools, shrinks tightly around thebearing 11. It will be understood that no coating has been employedbetween the outer surface of the bearing 11 and the cast face of thehousing 10' and the bearing 11 as employed in the practice of thepresent invention is dry during casting, and subsequently impregnatedwith oil.

The assembly of the housing and bearing as shown in FIG. 2 is then, inaccordance with the present invention, radially compressed aftercasting, by applying pressure to the outside of the housing 10,particularly the portion thereof which embraces the bearing 11, and byalso applying pressure to the end of the bearing 11 in an axialdirection and in a further radial direction from inside the bore 14 ofthe bearing 11.

Thus, the unit as shown in FIG. 2 is forced into the cavity 17 of thedie 18 by means of a ram 19, the cavity of the die 18 being slightlysmaller than the outer dimensions of the housing 10. The reduction insize of the housing 10 as a result of the aforesaid compression, is suchas to maintain the metal of the housing 10 within its elastic limits sothat no permanent set is retained after removing the housing 10 from thedie 18.

A shouldered punch 20 is then inserted into the bore 14 of the bearing11 until the shoulder 21 thereof contacts an end of the bearing 11. Thepunch which is endwise tapered as at 22 has a diameter slightly largerthan that of the bore 14 so that it results in radial compression in anoutward direction and opposite to the radial compression resulting fromforcing the housing 10 into the die 18.

The shouldered punch 20 is slightly out-of-round so that when forcedinto the bearing 11 it induces in the latter a slightly out-of-roundshape which is retained therein due to compression of the bearing 11beyond its elastic limit.

Thus, when the punch 20 is removed from the bearing 11, and the housing10 is removed from the die 18, the housing 10 will return to itsoriginal size and contour but the bearing 11 will retain about 20% ofits compression and slightly outf-round condition. This set compressionin the bearing, as a result of its resilient character, causes it tothereby separate from the confines of the spherical bore 14 of thehousing but to be retained therein in a pivotal manner. Further due tothe resulting out-of-round character of the bearing 11, it is preventedthereby from spinning within the housing 10. At the same time, thestrain of shrinkage of the housing 10 is relieved.

In a modified practice, the precast assembly of the housing 10 about thebearing 11 is forced into the cavity 17 of the die 18 in the mannerpreviously described. However, in this case the cavity 17 of the die isslightly out-of-round so that the housing 10 becomes temporarily pressedto out-of-round condition. Thereafter, a shouldered punch similar tothat of punch 20 is forced into the in this case the punch 20 iscylindrical in cross section,

except for a slight taper. The diameter of the punch 20 is of courseslightly greater than that of the bore 14 in this modification so thatthe outer surface of bearing 11 becomes deformed to an out-of-roundcondition since it is restricted by the out-of-round compressed housingfrom expanding equally. The sintered powdered metal composition of thebearing 11 while being resilient and returning to some of its originalform, nevertheless does not return to its completely original form butremains with its outer surface deformed and out-of-round. Thus, while itbecomes in this operation separated from the housing 10, it isnevertheless retained therein in a pivotal manner, firstly by thehousing 10, and secondly is retained against spinning on its axis byreason of its out-of-round character and relatively small degree ofseparation from the confines of the housing 10.

In another modified method, similar but not fully equivalent results maybe accomplished with or without restraining the housing 10. In thiscase, the die 18 having a cavity 17 may be employed but wherein thecavity 17 is of equal dimension to the outer diameter of the housing 10so that it merely forms a seat therefor. In the alternative, otherholding means may be employed. In this modified method, the sinteredpowdered metal bearing 11 only is compressed by restraining its axialmovement at one end by means of, for example, the die 18, or othermeans, and a shouldered punch similar to punch 20 of slightly largerdiameter than the inside diameter of the bore 14 is forced into thebearing 11. This compresses the bearing to a degree beyond its elasticlimit and when the punch is withdrawn the bearing Will spring backsufficiently to relieve the restraining force of the compression of thehousing 10 and separate itself from the housing. In this case, thehousing and bearing remain round, but the amount of expansion andspring-back is controlled to retain sufficient friction of the bearing14 against the confines of housing 10 so as to prevent the bearing 11from spinning on its axis while remaining pivotally retained in thehousing 10.

However, due to the pivotability of the bearing 11 within the housing 10in each case, it is possible to compensate for initial or subsequentminor misalignment of a shaft journaled in the bearing 11 and to therebyrelieve undue stress on either the bearing or the shaft or both. Thehousing 10 needs only to be bolted in place by means of suitable boltsengaged through the holes 13 in the integral flanges 12 to provide abearing surface for a rotatable shaft. Thus, the device of the presentinvention provides a self-aligning bearing surface with a simple meansby fastening the bearing to a suitable support and eliminates the needfor costly alignment since the unique construction and arrangement ofthe parts automatically provides for self-alignment and the assemblyrelieves undue stress of the engaged rotating shaft in the bearingthrough application of a ball-joint-like unit.

Although I have shown and described the preferred embodiment of myself-aligning pillow block and preferred method and means for formingthe same, it will be understood by those skilled in the art that variouschanges may be made in the details thereof without departing from thespirit and scope of my invention as comprehended by the following claim.

I claim:

A self-aligning pillow block comprising a one-piece rigid cast metalbearing block formed with a spherical bore, and a bearing composed ofporous sintered powdered metal formed with a cylindrical axial bore anda substantially spherical outer surface of greater segment than that ofsaid spherical bore snugly and pivotally disposed in and embraced by thedefines of said spherical bore, said bearing being out-of-round asviewed in transverse cross-section so as to be of ellipsoidal shape, thediametrically opposed radially outermost portions of the ellipsoidallyshaped bearing being in frictional engagement with the inner surface ofthe spherical bore of the bearing block, whereby to retain the bearingagainst spinning on its axis.

References Cited UNITED STATES PATENTS Claus 30'872 Claus 30872 Smith30872 Fast 308--72 X 6 2,596,202 5/1952 Bolte 30872 3,141,231 7/1964Davies et a1. 30872 X FOREIGN PATENTS 911,204 3/1946 France.

MARTIN P. SCHWADRON, Primary Examiner.

R. F. HESS, Assistant Examiner.

